Molecular and General Genetics MGG

, Volume 247, Issue 6, pp 670–679

Sequencing and analysis of the gene encoding the α-toxin of Clostridium novyi proves its homology to toxins A and B of Clostridium difficile

  • Fred Hofmann
  • Andrea Herrmann
  • Ernst Habermann
  • Christoph von Eichel-Streiber
Original Paper


A library of total Clostridium novyi DNA was established and screened for the α-toxin gene (tcnα) by hybridization with oligonucleotides derived from a partial N-terminal sequence and by using specific antisera. Overlapping subgenic tcnα fragments were isolated and subsequently the total sequence of tcnα was determined. The 6534 nucleotide open reading frame encodes a polypeptide of Mr 250 166 and pI 5.9. The N-terminal α-toxin (Tcnα) sequence MLITREQLMKIASIP determined by Edman degradation confirmed the identity of the reading frame and the assignment of the translation start point. The toxin is not modified posttranslationally at its N-terminus nor does it consist of different subunits. Overall the amino acid sequence shows 48% homology between the Tcnα and both toxins A (TcdA) and B (TcdB) of Clostridium difficile. The C-terminal 382 residues of Tcnα constitute a repetitive domain similar to those reported for TcdA and TcdB of C. difficile. The individual repeat motifs of these three toxins consist of oligopeptides some 19–52 amino acids in length, arranged in four to five different groups. Genetic, biochemical and pharmacological data thus confirm that the three toxins belong to one subgroup, designated large clostridial cytotoxins (LCT). Further definition of their structure and detailed molecular action should allow the LCTs to be used tools for the analysis of microfilament assembly and function.

Key words

Virulence factor Repetitive domain Large clostridial cytotoxins Cytoskeleton Rho 


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Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Fred Hofmann
    • 1
  • Andrea Herrmann
    • 1
  • Ernst Habermann
    • 2
  • Christoph von Eichel-Streiber
    • 1
  1. 1.Verfügungsgebäude für Forschung und Entwicklung, Institut für Medizinische Mikrobiologie und HygieneJohannes Gutenberg -Universität MainzMainzGermany
  2. 2.Klinische PharmakologieJustus Liebig Universität GießenGießenGermany

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